Influence of zinc and iron enrichments on phytoplankton growth in the northeastern subarctic Pacific

Near-surface seawater from the northeastern subarctic Pacific was incubated on deck for 8 d, supplemented with (1) control, no additions (2) �Zn (3) �Fe (4) �Zn�Fe. Concentrations of total Zn and Fe at time zero (t0) and in the control remained at �0.1–0.2 nmol L�1. In the control, chlorophyll (�0.3...

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Bibliographic Details
Main Authors: D. W. Crawford, M. S. Lipsen, D. A. Purdie, M. C. Lohan, P. J. Statham, F. A. Whitney, J. N. Putland, W. K. Johnson, N. Sutherl, T. D. Peterson, P. J. Harrison, C. S. Wong
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Subjects:
Pacific
Subarctic
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.314.4485
http://aslo.org/lo/toc/vol_48/issue_4/1583.pdf
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Summary:Near-surface seawater from the northeastern subarctic Pacific was incubated on deck for 8 d, supplemented with (1) control, no additions (2) �Zn (3) �Fe (4) �Zn�Fe. Concentrations of total Zn and Fe at time zero (t0) and in the control remained at �0.1–0.2 nmol L�1. In the control, chlorophyll (�0.3 mg m�3), 14C uptake into POC and PIC, and inorganic nutrients all remained relatively constant. Addition of Zn slightly but significantly increased chlorophyll (p � 0.05), decreased phosphate (p � 0.01) and nitrate (p � 0.05), and in P versus E experiments, chl increased Pm �10-fold and Pm 2–3-fold. The abundance of small diatoms and coccolithophores was higher in the �Zn treatment compared to the control. The �Fe and �Zn�Fe treatments, compared to the control, both showed �10-fold increases in chlorophyll and 14C uptake into POC and PIC and complete removal of nitrate (�0.2 mmol m�3). However, differences were observed in size-fractionated data; the �Zn�Fe treatment had significantly lower percent chlorophyll in the �20-�m fraction (p � 0.01) and a higher percentage in the 0.2–5-�m fraction (p �

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